Effects of 29-h total sleep deprivation on local cold tolerance in humans

To study the effects of a 29-h total sleep deprivation (TSD) on local cold tolerance, 10 healthy men immersed their right hand for 30 min in a 5°C water bath (CWI) after a 30-min rest period in a thermoneutral environment (Control), after a normal night (NN) and after a 29-h TSD. CWI was followed by a 30-min passive rewarming (Recovery). Finger 2 and 4 skin temperatures (Tfi2, Tfi4) and finger 2 cutaneous vascular conductance (CVC) were monitored to study cold-induced vasodilation (CIVD). Rectal temperature (Tre), mean skin temperature ( $$ \bar{T}{sk} $$ ), heart rate (HR) and blood pressure (BP) were also measured. Blood samples were collected at the end of the Control, at the lower and at the first maximal Tfi2 values during CWI and at Recovery. Tfi2, Tfi4 and CVC did not differ after TSD at Control, whereas they were reduced during CWI (−2.6 ± 0.7°C for Tfi2; −2 ± 0.8°C for Tfi4, −79 ± 25% for relative CVC, P